Query modification based on textual resource context

ABSTRACT

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for modifying a query based on textual resource content. In one aspect, a method includes receiving, from a user device, a query including a plurality of terms; determining an active textual resource displayed in an application environment on the user device; determining to modify the query received from the user device, and in response: determining, based on the textual resource, modification data for the query, generating a set of modified queries based on the query and the modification data, scoring the modified queries according to one or more scoring criteria, selecting one of the modified queries based on the scoring, and providing, to the user device, search results responsive to the selected modified query.

BACKGROUND

This specification relates to search query processing.

The Internet provides access to a wide variety of resources, for example, video files, image files, audio files, or Web pages, including content for particular subjects, book articles, or news articles. A search system can select one or more resources in response to receiving a search query. A search query is data that a user submits to a search system to satisfy the user's informational needs. The search queries are usually in the form of text, e.g., one or more query terms. The search system selects and scores resources based on their relevance to the search query and on their importance relative to other resources to provide search results. The search results are typically ordered according to the scores and presented according to this order.

SUMMARY

This specification describes technologies relating to modifying queries based on the context of a textual resource displayed on a user device from which the query is received.

In general, one innovative aspect of the subject matter described in this specification can be embodied in methods that include the actions of receiving, from a user device, a query including a plurality of terms; determining an active textual resource displayed in an application environment on the user device; determining to modify the query received from the user device, and in response: determining, based on the textual resource, modification data for the query, generating a set of modified queries based on the query and the modification data, scoring the modified queries according to one or more scoring criteria, selecting one of the modified queries based on the scoring, and providing, to the user device, search results responsive to the selected modified query. Other embodiments of this aspect include corresponding systems, apparatus, and computer programs, configured to perform the actions of the methods, encoded on computer storage devices.

Particular embodiments of the subject matter described in this specification can be implemented so as to realize one or more of the following advantages. Search queries can be input in a “conversational” manner, which results in a more fluid and intuitive user experience. The modification of a query may optionally be subject to a conversational signal, which precludes the modification of queries that are well formed or that otherwise exhibit a signal that the query is complete and should not be modified. Limiting the modifications to the context of the text resource reduces the likelihood of topic drift or extraneous search results that may not be of interest to the user.

The details of one or more embodiments of the subject matter described in this specification are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an example environment in which a search system 110 modifies queries based on a textual resource context.

FIG. 2 is a block diagram of an example contextual query modifier.

FIG. 3 is a flow diagram of an example process for modifying a query based on a textual resource context.

FIG. 4A is an illustration of a display environment in which a resource is displayed and a query is input.

FIG. 4B is an illustration of a display environment in which a search result for a modified query is displayed.

Like reference numbers and designations in the various drawings indicate like elements.

DETAILED DESCRIPTION

Described below are systems and methods for modifying a query based on a context of a textual resource. A search system receives a query, and determines that an active textual resource is displayed in an application environment on the user device in which the query was input. An active textual resource is a resource that is displayed in an active environment, such as an active window, or that is either implicitly or explicitly specified for defining a context for the query.

In some implementations, the system determines whether to modify the query received from the user device. For example, the system may skip the context modification for queries that are not ambiguous with respect to a term. Conversely, when a query includes an ambiguous term, or otherwise evidences a signal that it should be modified based on the context of the textual resource, the system will perform a context modification.

When performing a context modification, the system determines, based on the textual resource, modification data for the query, and generates a set of modified queries based on the query and the modification data. A variety of modification data types and query modification algorithms can be used. The system then scores the modified queries according to one or more scoring criteria. The score for each query may be based on the results of a search operation performed for each query, the similarity of the query to other, previously received queries, and other criteria. A modified query with a highest score relative to the other modified queries is selected, and search results responsive to the selected modified query are provided to the user device from which the original query was received.

These features and additional features are described in more detail below.

FIG. 1 is a block diagram of an example environment in which a search system 110 modifies queries based on textual resource context. A computer network 102, such as wide area network (WAN), the Internet, or a combination thereof, connects publisher web sites 104, user devices 106, and the search system 110. The online environment 100 may include many thousands of publisher web sites 104 and user devices 106.

A web site 104 is one or more web page resources 105 associated with a domain name, and each web site is hosted by one or more servers. An example web site is a collection of web pages formatted in hypertext markup language (HTML) that can contain text, graphic images, multimedia content, and programming elements, such as scripts. Each web site 104 is maintained by a publisher, e.g., an entity that manages and/or owns the web site.

A resource is any data that can be provided by the publisher 104 over the network 102 and that is associated with a resource address. Resources include HTML pages, text documents, images, video, and feed sources, to name just a few. The resources can include content, such as words, phrases, pictures, and so on, and may include embedded information (such as meta information and hyperlinks) and/or embedded instructions (such as scripts).

A user device 106 is an electronic device that is under the control of a user and is capable of requesting and receiving resources over the network 102. Example user devices 106 include personal computers, mobile communication devices, and other devices that can send and receive data over the network 102. A user device 106 typically includes a user application, such as a web browser or some other application that can receive and display resources 105 over the network, to facilitate the sending and receiving of data over the network 102. The application can enable a user to display and interact with text, images, videos, music and other information typically located on a web page at a website on the network 102.

To facilitate searching of these resources 105, the search system 110 identifies the resources by crawling the publisher web sites 104 and indexing the resources provided by the publisher web sites 104. The indexed and, optionally, cached copies of the resources are stored in a resource index 112. Although one index 112 is shown, the index may include different corpora, such as a web page corpus, an image corpus, a video corpus, and the like.

The user devices submit search queries 109 to the search system 110. Search queries are submitted in the form of a search request for one or more resources responsive to the query. In response to the search request, the search system 110 uses the indexed cache 112 to identify resources that are relevant to the queries. The search system 110 identifies the resources in the form of search results and returns the search results to the user devices 106 in search results pages. A search result is data generated by the search system 110 that identifies a resource that satisfies a particular search query, and includes a resource locator for the resource. An example search result can include a web page title, a snippet of text extracted from the web page, and the URL of the web page.

The resources referenced by the search results are ranked based on scores related to the resources identified by the search results, such as information retrieval (“IR”) scores, and optionally a separate ranking of each resource relative to other resources (e.g., an authority score). In some implementations, the IR scores are computed from dot products of feature vectors corresponding to a query and a resource, and the ranking of the search results is based on relevance scores that are a combination of the IR scores and authority scores. The search results are ordered according to these scores and provided to the user device according to the order.

The user devices 106 receive the search results pages and render the pages for presentation to users. In response to the user selecting a search result at a user device 106, the user device 106 requests the resource identified by the resource locator included in the selected search result. The publisher of the web site 104 hosting the resource receives the request for the resource from the user device 106 and provides the resource to the requesting user device 106.

In some implementations, the queries 109 submitted from user devices 106 are stored in query logs 114. Click data for the queries and the web pages referenced by the search results are stored in click logs 116. The query logs 114 and the click data 116 define search history data 117 that include data from and related to previous search requests associated with unique identifiers. The click data define actions taken responsive to search results provided by the search system 110. The query logs 114 and click logs 116 can be used to map queries submitted by the user devices to web pages that were identified in search results and the actions taken by users (i.e., that data are associated with the identifiers from the search requests so that a search history for each identifier can be accessed). The click logs 116 and query logs 114 can thus be used by the search system to the sequence of queries submitted by the user devices, the actions taken in response to the queries, and how often the queries are submitted.

In additional to requesting general search results, users often use the search system to seek for “answers” rather than a breadth of information. An answer is a fact or relation that is responsive to a question. A “question query” differs from an informational query in that the question query seeks the answer, while the informational query is a request for a variety of different types of information for a subject. For example, the question query “How high is Pikes Peak” is a structured query that clearly requests a fact—the height of Pikes Peak. A search system can detect the structured nature of the query and interpret the query as a question query, and provide, in response to the query, a particular result that provides an answer to the question, and optionally other results.

In some implementations, the search system 110 includes a contextual query modifier 120 that modifies a received query based on a context defined by the textual content of an active resource. For example, as shown in FIG. 1, a resource 130 may be rendered on a user device 106 when the user inputs a search query 132 for an active textual resource 130. The search query 132 is typically a set of terms, e.g., Q:{T1 . . . Tn]. As will be described in more detail below, the contextual query modifier 120 determines an active textual resource for the query, and, if there is a signal that indicates a contextual modification of the query is required, the contextual query modifier 120 then generates a number of candidate modified queries, scores each candidate modified query, and selects the candidate modified query with the highest score as a modified query. The selected modified query is then processed as a search query and one or more results responsive to the query 142 are returned to the user device that submitted the query, e.g., in the form of a search results page 140.

The operation of the contextual query modifier 120 is described in more detail with reference to FIGS. 2, 3, 4A and 4B below. In particular, FIG. 2 is a block diagram 200 of an example contextual query modifier 120, and FIG. 3 is a flow diagram of an example process 300 for modifying a query based on a textual resource context. The process 300 is implemented in the example contextual query modifier 120 of FIG. 2. The functional architecture of FIG. 2 can be realized by programming a data processing apparatus to perform the functions described, and is but one example implementation of the contextual query modifier 120. Other functional distributions and subsystems can also be used.

In operation, the query evaluator 202 receives a query (302). For example, the search system 110 receives the query Q from the user device 106. With reference to FIG. 4A, the search system may receive the query 404 [When was he born] entered into the input field 402.

The query evaluator 202 determines an active textual resource for the query (304). An active textual resource is a resource that is displayed in an active environment, such as an active window, or that is either implicitly or explicitly specified defining a context for the query. For example, the received query may include data identifying a URL of the resource, such as the URL of a resource displayed in a browser when the query is input. By way of another example, the query evaluator 202 may determine an application context to which the query belongs. The application context corresponds to an application instantiated on the user device, such as a browser, social networking page, etc. The query evaluator 202 then determines the textual resource displayed in an application environment of the application. The application environment, for example, may be a window or other environment under control of an application and in which an application presents data. This can be done by, for example, issuing a request to the application for the address of the resource, or by some other appropriate process.

Again with reference to FIG. 4A, the active resource is the rendered resource 406 shown in the display environment 400. The active resource 406 includes the header “Entertainment Tidbits” and the content elements 410 and 412. The content elements 410 and 412 may be defined by the document object model, or some other formatting/markup convention. In FIG. 4A, the content elements 410 and 412 both include textual content and image content.

If there is no active textual resource, then in some implementations the query evaluator may determine to not modify a query. For example, suppose a user speaks into a smart phone [When was he born], but the user has no application open in which a textual resource is displayed. The query evaluator 202 will determine that no active resource is associated with the query, and thus no contextual modifications based on an active resource can be made.

The query evaluator 202 then determines whether to contextually modify the received query (306). Even if there is an active textual resource, the query may not need to be modified. For example, the query may be so well formed to provide a definite, unambiguous instruction, such as “What is the phone number of Joe's Bistro in San Francisco?” or “Search for newly released widgets.” Conversely, should the query include an ambiguous referring term, such as “[When was he born], where the pronoun “he” is ambiguous as to identify, then the query evaluator 202 determines the query should be modified based on the context of the textual resource. Likewise, should the query form an otherwise incomplete inquiry, such as “Phone number please,” then the query evaluator 202 determines the query should be modified based on the context of the textual resource.

A variety of appropriate algorithms can be used to determine whether a query is well formed to provide a definite, unambiguous instruction. For example, context free grammars, natural language processing, or even a list of queries can be used and applied to the received query.

Other appropriate ways of determining whether to modify a query can also be used. For example, in some implementations, the search system 110 will conduct a search based on the query, and the query evaluator 202 will evaluate the results. If the results do not meet one or more threshold, then the query may be modified. Example thresholds include a quality threshold that indicates a quality of the top-scoring resources identified as being responsive to the query; a topicality threshold that indicates that the top-scoring resources have a dominant intent of at least one topic, etc.

If the query evaluator 202 determines not to contextually modify the received query, then the query is processed without contextual modification (308). Conversely, if the query evaluator 202 does determine to contextually modify the received query, then the textural resource processor 204 determines modification data for the query (310). Appropriate modification data are data that can be used to generate modified queries from the received query. For example, the textural resource processor 204 may determine, from the text of the textual resource, entity text that describes entities. As used herein, entities are topics of discourse, concepts or things that can be referred to by a text fragment, e.g., a term or phrase, and are distinguishable from one another, e.g., based on context. Example entities include persons, places, locations, addresses, dates, and products. Entities may also be subjects of an entity relation graph, such as a knowledge graph. The textural resource processor 204 can access entity data that describes such entities, and process the active resource to identify textual data describing entities.

The modification data is not limited to entities, however. For example, metadata of the resource can be processed to determine other modification data, such as a domain name, which may correspond to a company name; product listing data that corresponds to a product listed in the resource; and so on. Topics can also be used as modification data. For example, a resource may have been categorized as belonging to one or more topics, and each topic name can be used as modification data. Again, the textural resource processor 204 can access such data for the resources to identify the modification data for the resource.

The modification data that are produced may thus define a set of values and/or parameters that can be used to modify the received query. As shown in FIG. 2, the modification data are illustrated as the dataset {D_Mod}. For example, assume entity detection is used. From the resource 406, the following entities are detected:

D_Mod={<Richard Roe>,

-   -   <BigMovieCo>,     -   <Jane Doe>,     -   <movie star>     -   <movie>     -   <graphic novel>,     -   <Famous Theater>,     -   <landmark>     -   <dollar>     -   <San Francisco>,     -   <June 1>}.

The candidate generator 206 generates a set of candidate modified queries based on the received query and the modification data (312). A variety of appropriate processes can be used to generate the candidate modified queries. In some implementations in which entity text are used for the modification data, entity text describing each entity is appended or prepended to the query. For example, for each entity described in the active textual resource, corresponding entity text can be concatenated with the query. Thus, for a set of entities

E={e1, e2, . . . en}

and a received query Q, the following set of candidate modified queries is generated:

CQ_Mod={Qe1, Qe2, . . . Qen}

For example, for the query Q [When was he born], the following queries are generated:

CQ_Mod={[When was he born Richard Roe],

-   -   [When was he born BigMovieCo],     -   [When was he born Jane Doe],     -   [When was he born movie star]     -   [When was he born movie]     -   [When was he born graphic novel],     -   [When was he born Famous Theater],     -   [When was he born landmark]     -   [When was he born dollar]     -   [When was he born San Francisco],     -   [When was he born June 1]}.

In some implementations, all candidate queries are provided to the candidate scorer 208. In other implementations, the candidate generator 206 (or the candidate scorer 208) can implement a filtering process to filter out queries that include latent or patent type mismatches of terms. The mismatches can be detected using language models, attribute and entity maps, and the like. For example, the query [When was he born BigMovieCo] has a patent mismatch between the pronouns “he” and “BigMovieCo,” and thus is removed from the scoring process.

In other implementations, a candidate query may be a query in which one or more terms are replaced based on the entity. For example, instead of [When was he born Richard Roe], the candidate query may be [When was Richard Roe born]. A variety of appropriate algorithms can be used to generate such query revisions. For example, context free grammars, natural language processing, or even a list of queries can be used and applied to the received query.

In still other implementations, query logs can be accessed to determine a similarity of a modified query (e.g., the text of the query and the entity text) to other prior queries stored in a query log. Prior queries for which the similarity measure meets a threshold similarity value may be selected as a candidate query. This type of candidate generation can optionally filter out “long tail” queries if the candidate query is a query that is rarely received, e.g., if the candidate query does not meet a minimum frequency threshold or instance count.

Other candidate query generation processes can also be used, and each of the candidate query generation processes described above can be used alone or in combination with each other.

The candidate modified queries are scored and a top scoring candidate modified query is selected (314). A variety of scoring processes can be used. In some implementations, each query is provided to the search system 110, which then scores resources for the query. For each query, the candidate scorer 208 receives search data describing relevance scores of the resources that are determined to be relevant to the modified query. Using this data, the candidate scorer generates a score for the modified query. Each score can be based on quality scores for the resources responsive to the query, where the quality score is an indicator of the quality of the resources relative to other resources. For example, a query for which a number of only low-quality resources are returned will be scored less than a query for which a number of high quality resources are returned.

Likewise, each score can be based on the number of resources that meet a relevance threshold. For example, when the relevance scores of resources are relatively low for a query, the query is likely a poorly formed query. Conversely, when the relevance scores of resources are relatively high for a query, the query is more likely to be a well formed query.

In some implementations, the candidate score 208 may take into account whether the query triggers a special search operation or action. The triggering of a special search operation by the candidate modified query can be interpreted as a signal that the candidate modified query is a well formed query for the special operation. For example, if a first candidate modified query is interpreted as a question query, and a second candidate modified query is not, then the score of the first candidate modified query may be boosted relative to the score of the second candidate modified query. Likewise, if a first candidate modified query is interpreted as an optional image search query, and a second candidate modified query is not, then the score of the first candidate modified query may be boosted relative to the score of the second candidate modified query. Similarly, if a first candidate modified query is interpreted as an action query that would invoke an action at the user device, and a second candidate modified query is not, then the score of the first candidate modified query may be boosted relative to the score of the second candidate modified query.

Other scoring processes can also be used, and each of the scoring processes described above can be used alone or in combination with each other.

The candidate modified query with the highest score relative to other candidate modification queries is selected by the candidate scorer 208, and is provided to the search system front end 210. The search system front end 210 then provides search results responsive to the modified query.

For example, as shown in FIG. 4B, the query [When was he born Richard Roe] is selected as the modified query 424. An answer box 430 is provided with the query, along with one or more search results 432.

The example of FIGS. 4A and 4B are described in the context of a question query. However, the same features apply equally to other queries and actions. For example, for a resource that describes a book, such as a book review, a user may input the query [Show me the text of this book], and the search system 110 will process a modified query that causes sample text of the book to be presented.

Likewise, and with reference to FIG. 4A, an action query, such as [Call that theater], may result in the user device taking an action that places a call to the “Famous Theater” theater. For example, metadata regarding the Famous Theater may include the phone number, and the modified query may be an action query that causes the user device to place a call to the phone number of the Famous Theater.

Embodiments of the subject matter and the operations described in this specification can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed in this specification and their structural equivalents, or in combinations of one or more of them. Embodiments of the subject matter described in this specification can be implemented as one or more computer programs, i.e., one or more modules of computer program instructions, encoded on computer storage medium for execution by, or to control the operation of, data processing apparatus.

A computer storage medium can be, or be included in, a computer-readable storage device, a computer-readable storage substrate, a random or serial access memory array or device, or a combination of one or more of them. Moreover, while a computer storage medium is not a propagated signal, a computer storage medium can be a source or destination of computer program instructions encoded in an artificially-generated propagated signal. The computer storage medium can also be, or be included in, one or more separate physical components or media (e.g., multiple CDs, disks, or other storage devices).

The operations described in this specification can be implemented as operations performed by a data processing apparatus on data stored on one or more computer-readable storage devices or received from other sources.

The term “data processing apparatus” encompasses all kinds of apparatus, devices, and machines for processing data, including by way of example a programmable processor, a computer, a system on a chip, or multiple ones, or combinations, of the foregoing. The apparatus can include special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit). The apparatus can also include, in addition to hardware, code that creates an execution environment for the computer program in question, e.g., code that constitutes processor firmware, a protocol stack, a database management system, an operating system, a cross-platform runtime environment, a virtual machine, or a combination of one or more of them. The apparatus and execution environment can realize various different computing model infrastructures, such as web services, distributed computing and grid computing infrastructures.

A computer program (also known as a program, software, software application, script, or code) can be written in any form of programming language, including compiled or interpreted languages, declarative or procedural languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, object, or other unit suitable for use in a computing environment. A computer program may, but need not, correspond to a file in a file system. A program can be stored in a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files that store one or more modules, sub-programs, or portions of code). A computer program can be deployed to be executed on one computer or on multiple computers that are located at one site or distributed across multiple sites and interconnected by a communication network.

The processes and logic flows described in this specification can be performed by one or more programmable processors executing one or more computer programs to perform actions by operating on input data and generating output. The processes and logic flows can also be performed by, and apparatus can also be implemented as, special purpose logic circuitry, e.g., a FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit).

Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. The essential elements of a computer are a processor for performing actions in accordance with instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto-optical disks, or optical disks. However, a computer need not have such devices. Moreover, a computer can be embedded in another device, e.g., a mobile telephone, a personal digital assistant (PDA), a mobile audio or video player, a game console, a Global Positioning System (GPS) receiver, or a portable storage device (e.g., a universal serial bus (USB) flash drive), to name just a few. Devices suitable for storing computer program instructions and data include all forms of non-volatile memory, media and memory devices, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry.

To provide for interaction with a user, embodiments of the subject matter described in this specification can be implemented on a computer having a display device, e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor, for displaying information to the user and a keyboard and a pointing device, e.g., a mouse or a trackball, by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback, e.g., visual feedback, auditory feedback, or tactile feedback; and input from the user can be received in any form, including acoustic, speech, or tactile input. In addition, a computer can interact with a user by sending documents to and receiving documents from a device that is used by the user; for example, by sending web pages to a web browser on a user's user device in response to requests received from the web browser.

Embodiments of the subject matter described in this specification can be implemented in a computing system that includes a back-end component, e.g., as a data server, or that includes a middleware component, e.g., an application server, or that includes a front-end component, e.g., a user computer having a graphical user interface or a Web browser through which a user can interact with an implementation of the subject matter described in this specification, or any combination of one or more such back-end, middleware, or front-end components. The components of the system can be interconnected by any form or medium of digital data communication, e.g., a communication network. Examples of communication networks include a local area network (“LAN”) and a wide area network (“WAN”), an inter-network (e.g., the Internet), and peer-to-peer networks (e.g., ad hoc peer-to-peer networks).

The computing system can include users and servers. A user and server are generally remote from each other and typically interact through a communication network. The relationship of user and server arises by virtue of computer programs running on the respective computers and having a user-server relationship to each other. In some embodiments, a server transmits data (e.g., an HTML page) to a user device (e.g., for purposes of displaying data to and receiving user input from a user interacting with the user device). Data generated at the user device (e.g., a result of the user interaction) can be received from the user device at the server.

While this specification contains many specific implementation details, these should not be construed as limitations on the scope of any inventions or of what may be claimed, but rather as descriptions of features specific to particular embodiments of particular inventions. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.

Thus, particular embodiments of the subject matter have been described. Other embodiments are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results. In addition, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In certain implementations, multitasking and parallel processing may be advantageous. 

What is claimed is:
 1. A method implemented in a data processing apparatus, the method comprising: receiving, from a user device displaying an active textual resource in an active window of an application environment on the user device, a query including a plurality of terms, the query input by a user on the user device displaying the active textual resource when the user input the query; determining that the query is an ambiguous query and that the user device is displaying, in the text of the active textual resource, entity text that describes entities and that the active textual resource was displayed when the query was input, and in response: identifying the entities described by entity text in the text of the active textual resource displayed in the active window of the application environment on the user device prior to receiving the query input by the user; automatically determining, for each entity described by the entity text in the text of the active textual resource displayed on the user device prior to receiving the query input by the user, modification data for each entity described by the entity text for the query; automatically generating, for each modification data for each entity described by the entity text in the text of the active textual resource, a set of modified queries based on the query and the modification data; automatically scoring the modified queries according to one or more scoring criteria; automatically selecting one of the modified queries based on the scoring; and providing, to the user device, search results responsive to the selected modified query.
 2. The method of claim 1, wherein identifying an active textual resource displayed in an application on the user device comprises: determining an application context to which the query belongs, the application context corresponding to an application instantiated on the user device; and determining an active textual resource displayed in an application environment of the application.
 3. The method of claim 1, wherein determining to modify the query received from the user device comprises determining that the query is a question query.
 4. The method of claim 1, wherein determining to modify the query received from the user device comprises: determining that the query is a question query; and determining that the question query includes an ambiguous referring term.
 5. The method of claim 1, wherein generating a modified query based on the query and the entity text describing the entity comprises concatenating the modified query with the entity text.
 6. The method of claim 1, wherein generating a modified query based on the query and the entity text describing the entity comprises revising one or more terms of the query based on the entity text describing the entity.
 7. The method of claim 1, wherein generating a modified query based on the query and the entity text describing the entity comprises: determining a similarity of the text of the query and the entity text to each of a plurality of prior queries stored in a query log; and selecting, form the query log, prior queries for which the similarity measure meets a threshold similarity value.
 8. The method of claim 1, wherein scoring the modified queries according to one or more scoring criteria comprises, for each modified query: receiving, from a search process, search data describing relevance scores of resources that are determined to be relevant to the modified query; and generating, from the search data, a score for the modified query.
 9. The method of claim 8, wherein generating, from the search data, a score for the modified query comprises: determining, for each resource, a quality score for the resource, the quality score being an indicator of quality of the resources relative to other resources; and generating the score for the modified query based, at least in part, on the quality scores.
 10. A system, comprising: one or more data processing apparatus; and one or more data stores in communication with the one or more data processing apparatus and storing instructions that upon execution cause the one or more data processing apparatus to perform operations comprising: receiving, from a user device displaying an active textual resource in an active window of an application environment on the user device, a query including a plurality of terms, the query input by a user on the user device displaying the active textual resource when the user input the query; determining that the query is an ambiguous query and that the user device is displaying, in the text of the active textual resource, entity text that describes entities and that the active textual resource was displayed when the query was input, and in response: identifying the entities described by entity text in the text of the active textual resource displayed in the active window of the application environment on the user device prior to receiving the query input by the user; automatically determining, for each entity described by the entity text in the text of the active textual resource displayed on the user device prior to receiving the query input by the user, modification data for each entity described by the entity text for the query; automatically generating for each modification data for each entity described by the entity text in the text of the active textual resource, a set of modified queries based on the query and the modification data; automatically scoring the modified queries according to one or more scoring criteria; automatically selecting one of the modified queries based on the scoring; and providing, to the user device, search results responsive to the selected modified query.
 11. The system of claim 10, wherein identifying an active textual resource displayed in an application on the user device comprises: determining an application context to which the query belongs, the application context corresponding to an application instantiated on the user device; and determining an active textual resource displayed in an application environment of the application.
 12. The system of claim 10, wherein determining to modify the query received from the user device comprises determining that the query is a question query.
 13. The system of claim 10, wherein determining to modify the query received from the user device comprises: determining that the query is a question query; and determining that the question query includes an ambiguous referring term.
 14. The system of claim 10, wherein generating a modified query based on the query and the entity text describing the entity comprises concatenating the modified query with the entity text.
 15. The system of claim 10, wherein generating a modified query based on the query and the entity text describing the entity comprises revising one or more terms of the query based on the entity text describing the entity.
 16. The system of claim 10, wherein generating a modified query based on the query and the entity text describing the entity comprises: determining a similarity of the text of the query and the entity text to each of a plurality of prior queries stored in a query log; and selecting, form the query log, prior queries for which the similarity measure meets a threshold similarity value.
 17. The system of claim 10, wherein scoring the modified queries according to one or more scoring criteria comprises, for each modified query: receiving, from a search process, search data describing relevance scores of resources that are determined to be relevant to the modified query; and generating, from the search data, a score for the modified query.
 18. A non-transitory computer storage medium encoded with instructions that when executed by one or more data processing apparatus cause the one or more data processing apparatus to perform operations comprising: receiving, from a user device displaying an active textual resource in an active window of an application environment on the user device, a query including a plurality of terms, the query input by a user on the user device displaying the active textual resource when the user input the query; determining that the query is an ambiguous query and that the user device is displaying, in the text of the active textual resource, entity text that describes entities and that the active textual resource was displayed when the query was input, and in response: identifying the entities described by entity text in the text of the active textual resource displayed in the active window of the application environment on the user device prior to receiving the query input by the user; automatically determining, for each entity described by the entity text in the text of the active textual resource displayed on the user device prior to receiving the query input by the user, modification data for each entity described by the entity text for the query; automatically generating, for each modification data for each entity described by the entity text in the text of the active textual resource, a set of modified queries based on the query and the modification data; automatically scoring the modified queries according to one or more scoring criteria; automatically selecting one of the modified queries based on the scoring; and providing, to the user device, search results responsive to the selected modified query. 